阿帕奇骆驼！配置负载均衡以尝试某些状态代码

http {
    upstream backend {
        server backend1.example.com;
        server backend2.example.com;
        server backend3.example.com;
    }

    server {
        listen 80;

        location / {
            proxy_pass http://backend;
            proxy_set_header Host $host;
            proxy_set_header X-Real-IP $remote_addr;
            proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
            proxy_set_header X-Forwarded-Proto $scheme;
        }
    }
}

<VirtualHost *:80>
    ServerName example.com

    ProxyPass / balancer://mycluster/
    ProxyPassReverse / balancer://mycluster/

    <Proxy balancer://mycluster>
        BalancerMember http://backend1.example.com
        BalancerMember http://backend2.example.com
        BalancerMember http://backend3.example.com
    </Proxy>
</VirtualHost>

error_page 503 = @maintenance;

location @maintenance {
    return 503 "Service Temporarily Unavailable";
}

ErrorDocument 503 "Service Temporarily Unavailable"

RewriteEngine On
RewriteCond %{REQUEST_URI} !^/maintenance\.html$
RewriteRule ^(.*)$ maintenance.html [R=503,L]